Leukemia سرطان الدم

Leukemia is a cancer of the blood or bone marrow. Bone marrow produces blood cells. Leukemia can develop due to a problem with blood cell production. It usually affects the leukocytes, or white blood cells.

Leukemia is most likely to affect people over the age of 55 years, but it is also the most common cancer in those aged under 15 years.

The National Cancer Institute estimates that 61,780 people will receive a diagnosis of leukemia in 2019. They also predict that leukemia will cause 22,840 deaths in the same year.

Acute leukemia develops quickly and worsens rapidly, but chronic leukemia gets worse over time. There are several different types of leukemia, and the best course of treatment and a person's chance of survival depends on which type they have.

In this article, we provide an overview of leukemia, causes, treatment, type, and symptoms

Causes

a man trying to look on the bright side of his leukemia diagnosis

Treament for leukemia depends on the type a person has.

Leukemia develops when the DNA of developing blood cells, mainly white cells, incurs damage. This causes the blood cells to grow and divide uncontrollably.

Healthy blood cells die, and new cells replace them. These develop in the bone marrow.

The abnormal blood cells do not die at a natural point in their life cycle. Instead, they build up and occupy more space.

As the bone marrow produces more cancer cells, they begin to overcrowd the blood, preventing the healthy white blood cells from growing and functioning normally.

Eventually, the cancerous cells outnumber healthy cells in the blood

Risk factors

There is a range of risk factors for leukemia. Some of these risk factors have more significant links to leukemia than others:

Artificial ionizing radiation: This could include having received radiation therapy for a previous cancer, although this is a more significant risk factor for some types than others.

Certain viruses: The human T-lymphotropic virus (HTLV-1) has links to leukemia.

Chemotherapy: People who received chemotherapy treatment for a previous cancer have a higher chance of developing leukemia later in life.

Exposure to benzene: This is a solvent that manufacturers use in some cleaning chemicals and hair dyes.

Some genetic conditions: Children with Down syndrome have a third copy of chromosome 21. This increases their risk of acute myeloid or acute lymphocytic leukemia to 2–3%, which is higher than in children without this syndrome.

Another genetic condition with links to leukemia is Li-Fraumeni syndrome. This causes a change to the TP53 gene.

Family history: Having siblings with leukemia can lead to a low but significant risk of leukemia. If a person has an identical twin with leukemia, they have a 1 in 5 chance of having the cancer themselves.

Inherited problems with the immune system: Certain inherited immune conditions increase the risk of both severe infections and leukemia. These include:

ataxia-telangiectasia

Bloom syndrome

Schwachman-Diamond syndrome

Wiskott-Aldrich syndrome

Immune suppression: Childhood leukemia may develop due to the deliberate suppression of the immune system. This might occur following an organ transplant as a child takes medications to prevent their body from rejecting the organ.

Several risk factors need further studies to confirm their link to leukemia, such as:

exposure to electromagnetic fields

exposure to certain chemicals in the workplace, such as gasoline, diesel, and pesticides

smoking

using hair dyes

Chronic and acute leukemias

During its lifespan, a white blood cell goes through several stages.

In acute leukemia, developing cells multiply quickly and collect in the marrow and blood. They exit the bone marrow too early and are not functional.

Chronic leukemia progresses more slowly. It allows for the production of more mature, useful cells.

Acute leukemia overcrowds the healthy blood cells more quickly than chronic leukemia.

Lymphocytic and myelogenous leukemias

Doctors classify leukemia according to the type of blood cell they affect.

Lymphocytic leukemia occurs if cancerous changes affect the type of bone marrow that makes lymphocytes. A lymphocyte is a white blood cell that plays a role in the immune system.

Myelogenous leukemia happens when the changes affect bone marrow cells that produce blood cells, rather than the blood cells themselves.

Acute lymphocytic leukemia

Children under 5 years old are at the highest risk of developing acute lymphoblastic leukemia (ALL). However, It can also affect adults, typically over the age of 50 years. Out of every five deaths from ALL, four occur in adults.

Chronic lymphocytic leukemia

This is most common among adults over 55 years, but younger adults can also develop it. About 25% of adults with leukemia have chronic lymphocytic leukemia (CLL). It is more common in men than in women and rarely affects children.

Acute myelogenous leukemia

Acute myelogenous leukemia (AML) is more common in adults than in children, but overall, it is a rare cancer. It develops more often in men than in women.

It develops quickly, and symptoms include fever, difficulty breathing, and pain in the joints. Environmental factors can trigger this type

Chronic myeloid leukemia

Chronic myelogenous leukemia (CML) mostly develops in adults. About 15% of all leukemia cases in the United States are CML. Children rarely develop this type of leukemia

Symptoms

Symptoms of leukemia include the following:

Poor blood clotting: This can cause a person to bruise or bleed easily and heal slowly. They may also develop petechiae, which are small red and purple spots on the body. These indicate that blood is not clotting properly.

Petechiae develop when immature white blood cells crowd out platelets, which are crucial for blood clotting.

Frequent infections: The white blood cells are crucial for countering infection. If white blood cells are not working correctly, a person may develop frequent infections. The immune system may attack the body's own cells.

Anemia: As fewer effective red blood cells become available, a person may become anemic. This means that they do not have enough hemoglobin in their blood. Hemoglobin transports iron around the body. A shortage of iron can lead to difficult or labored breathing and pale skin.

Other symptoms may include:

nausea

fever

chills

night sweats

flu-like symptoms

weight loss

bone pain

tiredness

If the liver or spleen becomes swollen, a person may feel full and eat less, resulting in weight loss.

Weight loss may also occur even without an enlarged liver or spleen. A headache may indicate that cancerous cells have entered the central nervous system (CNS).

However, all these can all be symptoms of other illnesses. Consultation and testing are necessary to confirm a diagnosis of leukemia.

What to know about leukemia

Last updated Wed 28 August 2019 By Adam Felman Reviewed by Yamini Ranchod, PhD, MS

Causes Risk factors Types Treatment Symptoms Diagnosis Outlook

Leukemia is most likely to affect people over the age of 55 years, but it is also the most common cancer in those aged under 15 years.

The National Cancer Institute estimates that 61,780 people will receive a diagnosis of leukemia in 2019. They also predict that leukemia will cause 22,840 deaths in the same year.

In this article, we provide an overview of leukemia, causes, treatment, type, and symptoms.

Causes

a man trying to look on the bright side of his leukemia diagnosis

Treament for leukemia depends on the type a person has.

Leukemia develops when the DNA of developing blood cells, mainly white cells, incurs damage. This causes the blood cells to grow and divide uncontrollably.

Healthy blood cells die, and new cells replace them. These develop in the bone marrow.

The abnormal blood cells do not die at a natural point in their life cycle. Instead, they build up and occupy more space.

As the bone marrow produces more cancer cells, they begin to overcrowd the blood, preventing the healthy white blood cells from growing and functioning normally.

Eventually, the cancerous cells outnumber healthy cells in the blood.

Risk factors

There is a range of risk factors for leukemia. Some of these risk factors have more significant links to leukemia than others:

Artificial ionizing radiation: This could include having received radiation therapy for a previous cancer, although this is a more significant risk factor for some types than others.

Certain viruses: The human T-lymphotropic virus (HTLV-1) has links to leukemia.

Chemotherapy: People who received chemotherapy treatment for a previous cancer have a higher chance of developing leukemia later in life.

Exposure to benzene: This is a solvent that manufacturers use in some cleaning chemicals and hair dyes.

Another genetic condition with links to leukemia is Li-Fraumeni syndrome. This causes a change to the TP53 gene.

Inherited problems with the immune system: Certain inherited immune conditions increase the risk of both severe infections and leukemia. These include:

ataxia-telangiectasia

Bloom syndrome

Schwachman-Diamond syndrome

Wiskott-Aldrich syndrome

Several risk factors need further studies to confirm their link to leukemia, such as:

exposure to electromagnetic fields

exposure to certain chemicals in the workplace, such as gasoline, diesel, and pesticides

smoking

using hair dyes

What are the side effects of chemotherapy?

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Types

There are four main categories of leukemia:

acute

chronic

lymphocytic

myelogenous

Chronic and acute leukemias

During its lifespan, a white blood cell goes through several stages.

In acute leukemia, developing cells multiply quickly and collect in the marrow and blood. They exit the bone marrow too early and are not functional.

Chronic leukemia progresses more slowly. It allows for the production of more mature, useful cells.

Acute leukemia overcrowds the healthy blood cells more quickly than chronic leukemia.

Lymphocytic and myelogenous leukemias

Doctors classify leukemia according to the type of blood cell they affect.

Lymphocytic leukemia occurs if cancerous changes affect the type of bone marrow that makes lymphocytes. A lymphocyte is a white blood cell that plays a role in the immune system.

Myelogenous leukemia happens when the changes affect bone marrow cells that produce blood cells, rather than the blood cells themselves.

Acute lymphocytic leukemia

Read more about ALL.

Chronic lymphocytic leukemia

Learn more about CLL here.

Acute myelogenous leukemia

Acute myelogenous leukemia (AML) is more common in adults than in children, but overall, it is a rare cancer. It develops more often in men than in women.

It develops quickly, and symptoms include fever, difficulty breathing, and pain in the joints. Environmental factors can trigger this type.

Here, learn more about AML.

Chronic myeloid leukemia

Chronic myelogenous leukemia (CML) mostly develops in adults. About 15% of all leukemia cases in the United States are CML. Children rarely develop this type of leukemia.

Treatment

surgeons performing modified radical mastectomy

Surgery is a possible treatment for some types of leukemia.

Treatment options will depend on the type of leukemia a person has, their age, and their overall state of health.

The primary treatment for leukemia is chemotherapy. A cancer care team will tailor this to suit the type of leukemia.

If treatment starts early, the chance of a person achieving remission is higher.

Types of treatment include:

Watchful waiting: A doctor may not actively treat slower growing leukemias, such as chronic lymphocytic leukemia (CLL).

Chemotherapy: A doctor administers medications intravenously (IV), using either a drip or a needle. These target and kill cancer cells. However, they can also damage noncancerous cells and cause severe side effects, including hair loss, weight loss, and nausea.

Chemotherapy is the primary treatment for AML. Sometimes, doctors may recommend a bone marrow transplant.

Targeted therapy: This type of treatment uses tyrosine kinase inhibitors that target cancer cells without affecting other cells, reducing the risk of side effects. Examples include imatinib, dasatinib, and nilotinib.

Many people with CML have a gene mutation that responds to imatinib. One study found that people who received treatment with imatinib had a 5-year survival rate of around 90%.

Interferon therapy: This slows and eventually stops the development and spread of leukemia cells. This drug acts in a similar way to substances that the immune system naturally produces. However, it can cause severe side effects.

Radiation therapy: In people with certain types of leukemia, such as ALL, doctors recommend radiation therapy to destroy bone marrow tissue before a transplant.

Surgery: Surgery often involves removing the spleen, but this depends on the type of leukemia a person has.

Stem cell transplantation: In this procedure, a cancer care team destroys the existing bone marrow with chemotherapy, radiation therapy, or both. Then, they infuse new stem cells into the bone marrow to create noncancerous blood cells.

This procedure can be effective in treating CML. Younger people with leukemia are more likely to undergo a successful transplant than older adults.

Symptoms

Symptoms of leukemia include the following:

Petechiae develop when immature white blood cells crowd out platelets, which are crucial for blood clotting.

Other symptoms may include:

nausea

fever

chills

night sweats

flu-like symptoms

weight loss

bone pain

tiredness

If the liver or spleen becomes swollen, a person may feel full and eat less, resulting in weight loss.

Weight loss may also occur even without an enlarged liver or spleen. A headache may indicate that cancerous cells have entered the central nervous system (CNS).

However, all these can all be symptoms of other illnesses. Consultation and testing are necessary to confirm a diagnosis of leukemia.

Diagnosis

doctor and patient discussing mucinous carcinoma

A doctor will carry out a physical examination to help diagnose leukemia.

A doctor will carry out a physical examination and ask about personal and family medical history. They will check for signs of anemia and feel for an enlarged liver or spleen.

They will also take a blood sample for assessment in the laboratory.

If the doctor suspects leukemia, they may suggest a bone marrow test. A surgeon extracts bone marrow from the center of a bone, usually from the hip, using a long, fine needle.

This can help them identify the presence and type of leukemia

سرطان الدم؟

سرطان الدم هو نوع من سرطانات خلايا الدم والأنسجة التي تنتج خلايا الدم مثل نخاع العظم.

في الشخص السليم، تنشأ خلايا الدم في نخاع العظم كخلايا جذعية وتنضج لاحقا لتشكل أنواع مختلفة من خلايا الدم (خلايا دم حمراء أو خلايا دم بيضاء أو صفائح) وتنتقل إلى مجرى الدم. في الشخص الذي يعاني من سرطان الدم، يبدأ نخاع العظم بإنتاج العديد من خلايا الدم البيضاء الشاذة التي تدخل إلى مجرى الدم وتبدأ بمزاحمة خلايا الدم الطبيعية السليمة، وتمنعها من القيام بوظائفها بالشكل الصحيح.

أنواع سرطان الدم:

هناك أنواع قليلة من سرطان الدم، وقد يكون حاداً أو مزمناً.

سرطان الدم الحاد (Acute leukemia ): ينمو ويتفاقم بسرعة كبيرة جداً، وقد يهدد الحياة لدرجة كبيرة. في هذا النوع يبدأ نخاع العظم بإنتاج أعداد كبيرة من خلايا الدم البيضاء غير الناضجة تسمى (blasts)، والتي تدخل إلى مجرى الدم. هذه الخلايا غير الناضجة تعمل بسرعة على مزاحمة الخلايا الطبيعية في مجرى الدم ولا تقوم بوظيفتها في محاربة العدوى أو إيقاف النزيف أو منح حدوث فقر الدم، ما يجعل الجسم ضعيفاَ جداً وغير محصن.

النوعان الأكثر شيوعاً لسرطان الدم الحاد هما:

سرطان الدم الليمفاوي الحاد (ALL)

سرطان الدم النقياني الحاد (AML)

سرطان الدم المزمن (Chronic leukemia ): يتطور ببطء ويتفاقم تدريجياً، وقد تحتاج الأعراض لفترة طويلة قبل أن تبدأ بالظهور. وفي بعض الأحيان يتم تشخيص سرطان الدم المزمن (من خلال الفحص الروتيني) قبل حتى ظهور أي أعراض. هذا لأن الخلايا السرطانية في هذه الحالة تكون ناضجة لدرجة كافية للقيام بوظائفها مثلها مثل خلايا الدم البيضاء الطبيعية، قبل أن تبدأ بالتفاقم.

هناك نوعان رئيسيان لسرطان الدم المزمن:

سرطان الدم الليمفاوي المزمن (CLL)

سرطان الدم النقياني المزمن (CML)

هناك نوع آخر يسمى سرطان دم الخلية الشعرية (Hairy cell leukemia)، وهو نوع نادر أخذ اسمه من شكله تحت المجهر. يصيب هذا النوع من سرطان الدم غالباً كبار السن، والرجال بشكل أكبر من النساء، حيث أن الأعراض والشكاوى الأكثر شيوعاً هي الضعف والإرهاق بسبب فقر الدم.

ما هي أسباب سرطان الدم؟

لا أحد يعرف على وجه التحديد مسببات سرطان الدم، إلا أن هناك عوامل خطورة معينة يُعتقد أنها تزيد من فرصة الإصابة به، وهي:

التعرض لمستويات عالية من الأشعة.

التدخين.

التعرض لمادة البنزين (وهي مادة كيماوية تستخدم بكثرة في الصناعات الكيماوية، وتتواجد أيضاً في دخان السجائر).

أنواع معينة من أدوية العلاج الكيماوي مثل (etoposide) وأدوية معروفة باسم (alkylating agents).

الأشخاص الذين يعانون من متلازمة خلل التنسج النقوي (myelodysplastic syndrome) وأنواع أخرى من اضطرابات الدم لديهم فرصة أكبر للإصابة بسرطان الدم النقياني الحاد.

وجود واحد أو أكثر من عوامل الخطورة لا يعني بالضرورة إصابة الشخص بسرطان الدم.

ما هي أعراض سرطان الدم؟

الشعور بالتعب والإعياء

فقدان الكثير من الوزن دون سبب

فقدان الشهية أو الشعور بالامتلاء بعد تناول القليل من الطعام

سهولة حصول النزيف والكدمات

عدوى متكررة

حمى أو تعرق ليلي غير مفسر

انتفاخ العقد الليمفاوية (خاصة في في الرقبة وتحت الإبط)

انتفاخ وانزعاج في البطن

تورم ونزيف في اللثة

كيف يتم تشخيص سرطان الدم؟

قد يقوم طبيبك ببعض الإجراءات التالية لتشخيص سرطان الدم:

فحوصات الدم: من بين فحوصات الدم التي تجرى في أغلب الأوقات هو فحص تعداد الدم الكامل (CBC) وفحص وظائف الكلى، وفحص وظائف الكبد وفحص تحديد مستوى حامض اليوريك. كما أن فحص مسحة الدم تحت المجهر ضروري للبحث عن أي خلايا سرطانية.

خزعة نخاع العظم هي أكثر الفحوصات شيوعاً لتحديد نوع سرطان الدم.

البزل القطني (Spinal tap) للبحث عن خلايا سرطانية في السائل الشوكي (cerebrospinal fluid) وهو السائل الذي يملأ الفراغات داخل وحول الدماغ والحبل الشوكي.

فحص الوراثيات الخلوية (Cytogenic analysis) حيث ينظر المختبر إلى الكروموسومات في الخلايا من عينات الدم أو نخاع العظم أو الغدد الليمفاوية لتحديد ما إذا كانت هناك أي مشاكل وراثية محددة. على سبيل المثال فإن الأشخاص الذين يعانون من سرطان الدم النقياني المزمن لديهم كروموسوم شاذ يسمى كروموسوم فيلادلفيا.

التشخيص الجزيئي (فحوصات PCR و FISH). يتمكن فحص تفاعل البلمرة المتسلسل (PCR) من الكشف عن آثار الخلايا السرطانية في الجسم، بينما يعمل فحص "مضان التهجين في الموقع" (FISH) بالكشف عن أي عيوب في الكروموسومات في الحمض النووي للخلية.

علاج سرطان الدم الليمفاوي الحاد: يتضمن علاج سرطان الدم الليمفاوي الحاد في مركز الحسين للسرطان ثلاث مراحل رئيسية: المعالجة الحثية (التحريضية)، والمعالجة ما بعد سكون المرض وعلاج المداومة (maintenance therapy). هذه العلاجات الثلاثة تتضمن استخدام العلاج الكيماوي والإشعاعي وزراعة نخاع العظم والخلايا الجذعية وغيرها من الأدوية العلاجية.

علاج سرطان الدم النقياني الحاد: في أغلب الأحيان يكفي العلاج الكيماوي لعلاج هذا النوع من السرطان لدى بعض المرضى. وفي بعض المرضى الآخرين يتم إجراء زراعة نخاع العظم أو الخلايا الجذعية لزيادة فرصهم في الشفاء أو في حالة الانتكاس أو تفاقم المرض. من الشائع أن يحتاج المرضى للدعم من خلال نقل الدم أو الصفائح والمضادات الحيوية في حال العدوى.

علاج سرطان الدم النقياني المزمن: الهدف من علاج سرطان الدم النقياني المزمن هو القضاء على خلايا الدم التي تحتوي على الجينات الشاذة. وكونه مرض "مزمن"، فإن العلاج لن يشفي المريض، ولكنه قد يتمكن من عيش حياة طبيعية إلى حد ما. يتعلم المرضى كيفية التعامل مع الآثار الجانبية للعلاج طويل الأمد، كما قد يتضمن العلاج زراعة نخاع العظم والعلاج الكيماوي والحيوي. وتعتبر الزراعة طريقة مهمة للأشخاص الأقل سنا، بينما يستفيد المرضى الأكبر سنا من العلاج الأقل عدوانية والذي قد يبقي مرضهم تحت السيطرة لفترة طويلة من الزمن.

علاج سرطان الدم الليمفاوي المزمن: تستخدم طرق مختلفة لعلاج سرطان الدم الليمفاوي المزمن، أكثرها شيوعا العلاج الكيماوي والعلاج الإشعاعي والعلاجات الموجهة (وهي العلاجات التي تستهدف خلايا سرطانية محددة دون التأثير على الخلايا الأخرى)، في بعض الأحيان قد تلزم الجراحة لإزالة طحال متضخم.

علاج سرطان دم الخلية الشعرية: بسبب النمو البطيء لهذا النوع من السرطان، قد لا يحتاج بعض المرضى إلى أي علاج، ولكن أغلبهم سيحتاجون إليه. ومع أن هذا النوع لا يرجى شفاؤه، إلا أن العلاج يضعه في حالة سكون لفترة طويلة، ويتضمن العلاج الكيماوي والحيوي، وفي بعض الأحيان التدخل الجراحي لإزالة الطحال